Connected: An Internet Encyclopedia
RFC 1123 - 4.1.2.6 PASV Command: RFC-959 Section 4.1.2

Top: Connected: An Internet Encyclopedia
Up: Requests For Comments
Up: RFC 1123
Up: 4. FILE TRANSFER
Up: 4.1 FILE TRANSFER PROTOCOL -- FTP
Up: 4.1.1 INTRODUCTION
Prev: 4.1.2.5 Data Connection Management: RFC-959 Section 3.3
Next: 4.1.2.7 LIST and NLST Commands: RFC-959 Section 4.1.3

### 4.1.2.6 PASV Command: RFC-959 Section 4.1.2

A server-FTP MUST implement the PASV command.

If multiple third-party transfers are to be executed during the same session, a new PASV command MUST be issued before each transfer command, to obtain a unique port pair.

IMPLEMENTATION:

  The format of the 227 reply to a PASV command is not well standardized. In particular, an FTP client cannot assume that the parentheses shown on page 40 of RFC-959 will be present (and in fact, Figure 3 on page 43 omits them). Therefore, a User-FTP program that interprets the PASV reply must scan the reply for the first digit of the host and port numbers.

  Note that the host number h1,h2,h3,h4 is the IP address of the server host that is sending the reply, and that p1,p2 is a non-default data transfer port that PASV has assigned.

Next: 4.1.2.7 LIST and NLST Commands: RFC-959 Section 4.1.3

Connected: An Internet Encyclopedia
RFC 1123 - 4.1.2.6 PASV Command: RFC-959 Section 4.1.2